Typical rotating machinery includes a rotor shaft and a quill shaft which transmits power from a driver shaft to the rotor shaft. The quill shaft is coupled to the rotor shaft and to the driver shaft by means of splines. With the arrangement described, the quill shaft is effectively hinged at the splines to permit a certain amount of misalignment between the rotor and driver shafts. Usually the quill shaft is a long and slender member and torsional damping means is required to eliminate the possibility of exciting torsional resonant frequencies. This damping means includes a plate mounted to the quill shaft, and having a surface adjacent a surface on a plate mounted to the rotor shaft. A spring provides an axial force which maintains a prescribed load on the adjacent surfaces of the respective plates whereby the desired damping is provided.
In equipment of the type described, it is desirable that the plate mounted to the rotor shaft follow the static and dynamic angular displacement of the plate mounted to the quill shaft, which may occur due to shaft misalignment. Further, it is desirable to provide additional torsional damping and to provide axial damping. The present invention achieves these results by mounting the plate to the rotor shaft in a particular and novel manner.